earth-moon animation

I am trying to create a keynote animation to illustrate the movements of the earth and moon. Keynote allows me to (easily) apply the "action" of rotate to create the exact effect I want: the earth circling the sun, and the moon circling the moon (separately).

But here's the thing: is there a way to have the moon circle the earth WHILE the earth is circling the sun? Keynote won't let me apply an "action" to an object already moving! Is there a workaround? Any help would be super appreciated!